Improve the design and visibility of enabled radio buttons and checkboxes

The current design of the radio buttons are light blue and fuzzy, which makes them difficult to identify and difficult to differentiate their different states, such as disabled. Checkmarks in the checkboxes are also light blue.

My patch changes the radio buttons to be solid inset circles that match the default font colour. My new checkboxes also match the colour of the radio buttons.

I have also fixed the focus outline for these two elements from an ugly square box to a fitting shape of the element, while maintaining the size and colour of the focus highlight.

Before - checkbox in focus:

After - checkbox in focus:

Before - radio button in focus:

After - radio button in focus: